When installing a roof, roof membranes are applied over the base structure. Roof membranes, which are made of polymeric materials such as ethylene propylene diene monomer (EPDM), repel water, snow, and generally protect the integrity of the underlying structure.
To properly install roof membranes, a fastening device such as a plate, batten bar, or other type of mechanical affixment secures one edge of a membrane to the underlying structure. An edge of a second membrane is then placed over the first membrane and the fastening device. The membranes are then welded to one another by applying a solvent/adhesive and/or by applying heat. The welding process is complicated by the presence of the fastener along the edge of the bottom membrane. As such, it is difficult to obtain a uniform and continuous seam/weld between the adjoining membranes.
One attempt at avoiding obstructions and fasteners is disclosed in U.S. Pat. No. 4,834,828, in which a bifurcated heat element seams the membranes while avoiding the fastening device. Although effective, the disclosed seaming device is deficient inasmuch as some fastening devices do not extend along the entire edge of the membrane and a gap or bubble may form along the welded seam. Accordingly, a secure seal is not obtained by virtue of elements infecting the gap between the seams and allows the membranes to be subjected to uplift pressures and other natural elements. This deteriorates the integrity of the seam which ultimately damages the underlying structure.
A continuous welding machine that can accommodate fastening devices when encountered and provide a continuous weld when obstructions are not present remains an unmet need in the art.